Chapter 2 The Realms and Definitions of Asphaltenes

• Published in: Developments in Petroleum Science Vol. 40; pp. 7 - 28
• Main Author: Yen, T.F.
• Format: Book Chapter
• Language: English
• Published: Elsevier Science & Technology 2000
• ISBN: 9780444503244; 0444503242
• ISSN: 0376-7361
• DOI: 10.1016/S0376-7361(09)70273-0

This chapter deals with the realms of asphaltenes. Asphalt can be divided into three fractions: (1) neutral resins, which is insoluble in alkalies and acids and completely miscible with petroleum oil, including the C5 fraction; (2) asphaltenes, which is insoluble in light gasoline and petroleum ether; and (3) carboids, or free carbons, which is readily found at higher temperatures, completely insoluble in benzene. Natural asphalt is normally composed of organic and mineral matter and contains variable amounts of water. The organic portion is composed of a complex mixture of hydrocarbons, asphaltenes, and resins with significant quantities of sulfur, oxygen, and nitrogen compounds. The chemical structure of asphaltene depends on the individual sources. The formation of the heterocyclic system in petroleum is known to have a biogenic and an abiogenic origin. The different stages in which different petroleum products are isolated indicate that both polycondensation and degradation occur. The intermediate products could be polycyclic aromatic hydrocarbons (PAH) or polynuclear aromatics (PNA) and carbons with defects in the carbonization stages.